How to prevent a bad and unffair review from troubled guests?

[Oriana6]

I had 2 very troubled guests.
They stayed for a week and unfortunately I couldn't be there, we didn't even meet.
They thought they would be alone in a house with 5 rooms. I suppose they thougth the rooms were for books or something. They were angry because of this. And also because, during their stay, a light in the corridor went off and wasn't working.
And they want their money back also because I gave them only 2 towesl each (1 for bath and 1 for face), and that I should inform guests that they only have 2 towels each.
They are obviouly going to give me a terrible review. What can I do to prevent this from happening? I have had 3 unsatisfied guests in 360 I hosted. Everyone that came to this house, left very happy, because I basically love doing this, so I think I do it well. It's really unfair.

[Sylvia318]

I don't know what to do Oriana and I have a similar problem. One host (only one) was unfair with me . He rated me on 2 stars regarding to communication complaining about a message he "had sent" me and I didn't answer. This message was never sent and I do all the conversation using the AirBNB platform, so it can be proved, but I have noone to complain too. How do we do when we receive this kind of unfair hosts evaluation, does somebody know?